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Might as well put in a higher compression piston while it's apart. A 10.5:1 piston will still run happily on 87 octane gasoline, you'll have more power everywhere, and it will get better fuel mileage. I didn't even have to touch the jetting after mine was installed.

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Seeing how much dirt that engine ingested I'll bet my bottom dollar that the piston to cylinder spec is huge along with the ring end gaps. No way will a hone and that piston be usable without a mile of clearance.

I don't have a bore gauge to measure it but I wouldn't be afraid to re ring it and roll on dependability wise. But to your point the current ring gap with the old ring is at twice the initial set up specification. From what I have found anyway.

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Ya but your get more air and MO POWAH! (at the expense of longevity lol)

Giving up some longevity is a price worth paying though. I still run my K&N's on all my road bikes. There was one on this bike when I bought it in Reno and the guy gave me the freshly oiled foam one in a bag. I rode it home to the Willamette valley and swapped in the foam. I don't ride it on the street cause tires. Better than a paper element! Your bike is likely to die of old age before you get where your going!

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Giving up some longevity is a price worth paying though. I still run my K&N's on all my road bikes. There was one on this bike when I bought it in Reno and the guy gave me the freshly oiled foam one in a bag. I rode it home to the Willamette valley and swapped in the foam. I don't ride it on the street cause tires. Better than a paper element! Your bike is likely to die of old age before you get where your going!

I found K&N passed too much dirt for my upkeep wallet. I have them on a few street vehicles and I keep them heavily oiled. My 1978 CanAm came with one stock and it is my only offroad machine still with one. I was seeing carbs as dirty as yours with a well sealed K&N.

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The Je slug is a nice looking piece but their literature leaves a bit to be desired. The pistons are listed in metric but when you get the box the label is half metric and half english, with the bore now being labeled in English. I have not purchased many metric pistons but it seems that many, like this one, are over bored at intervals of one whole mm. Which I found to be a little odd. This makes the first and or minimal bore .040" over. In the case of the 650l it's 100mm bore goes to 101. If they went 100.5 you could potentially get a couple more re bores out of a cylinder. As long as .020" will bring it back. Which may not be that common for an air cooled dirt bike, I don't know.

Included with the piston was a two sided instruction sheet, which is clearly for automotive applications. The sheet assumes that the wrist pin is parallel with the front and back of the engine. This of course would mean, connecting rod thrust is right and left, vs the actual front and back.

Taking that into consideration, I clocked the ring gap orientation 90 degrees.

Currently I'm trying to determine what I'm going to do about my two missing cylinder bolt washers. A couple had stuck in the cylinder. Not wanting to leave them for fear of the falling out at the machine shop, I fiddled them out of there. Apparently I did not put them in the cylinder bolt baggy when I got them out.

What I have found available locally with the correct i.d and o.d. are thinner. This leaves me with .040" more thread protrusion. or if I stack them .040" under. Which equals one thread at whatever metric pitch these are.

There is likely enough hole depth. I have not attempted to measure yet. Don't want to give up a thread but it may be safer.

In the morning I will call the Honda shop to see if they have some, if not ill try to get a good measurement of hole depth.

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The Je slug is a nice looking piece but their literature leaves a bit to be desired. The pistons are listed in metric but when you get the box the label is half metric and half english, with the bore now being labeled in English. I have not purchased many metric pistons but it seems that many, like this one, are over bored at intervals of one whole mm. Which I found to be a little odd. This makes the first and or minimal bore .040" over. In the case of the 650l it's 100mm bore goes to 101. If they went 100.5 you could potentially get a couple more re bores out of a cylinder. As long as .020" will bring it back. Which may not be that common for an air cooled dirt bike, I don't know.

Included with the piston was a two sided instruction sheet, which is clearly for automotive applications. The sheet assumes that the wrist pin is parallel with the front and back of the engine. This of course would mean, connecting rod thrust is right and left, vs the actual front and back.

Taking that into consideration, I clocked the ring gap orientation 90 degrees.

Currently I'm trying to determine what I'm going to do about my two missing cylinder bolt washers. A couple had stuck in the cylinder. Not wanting to leave them for fear of the falling out at the machine shop, I fiddled them out of there. Apparently I did not put them in the cylinder bolt baggy when I got them out.

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Well I hope to fire up the new and improved pig tomorrow. I really wanted to do a carb swap while I had it off. Man those vacuum slide carbs are a ridiculous tight fit.

I was pleased to find the carb in better shape that I thought. So much dirt inside everything, unreal. One whole side of the slide was covered in black striations. I had assumed this was where the coating had worn down to the black base plastic. But it was actually black dirt build up. I didn't know until I started scrubbing with a 3m pad and detergent. It came out real nice.

Parts guy had not heard of an xr650l. He asked me who the manufacturer was.

They did not have a rocker cover gasket.

I was more surprised by this fact.

Of course he thought it was because my bike was so old. Then I pointed out that it was the same gasket as in the new 2018 that was parked 15 feet from us. Then he seemed to agree.

They did however have a new 2000ish cr500 in the crate on a shelf and an espresso stand on the sales floor.

No gasket no washers

$45 made in china gasket. Washers $4 ea.

I found two other shops that had the gasket in stock. One for $38. I got that one. I used hardware store washers.

Shop manuals.

I have a Haynes and a Honda. They are actually 600r manuals from when I had one.

The Haynes verbiage is really good. In regards to the cam tensioner tool. It informs you that you will need a way to hold the tension lever against its spring. Then tells you Honda makes a tool for this purpose, but you may be able to fabricate your own. But be sure it holds it securely, a sudden release could lead to an injury. I am in step with this line of thinking.

However, the Haynes does not have exploded diagrams. Probably harder to generate than photos. But their photos are way better than Hondas.

The Honda manual.

Its been quite a few years since I used a manual edited by the Japanese. A line in Zen and the art of motorcycle maintenance comes to mind.

After a couple of pages of disassembly instructions for an assembly of parts, you get that final sentence.

To assemble reverse the order.

And surprisingly, or not, considering the previous sentence, Honda missed placing the cam in the proper position on assembly. Fortunately I was anticipating the instruction and caught the absence.

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Well it runs good. No noticeable power gain right off the bat but we will see what time brings as the rings seat. Starts immediately without the pilot full of dirt. It does pop out the exhaust when warm at idle then wants to die. Not sure what that is about.

I'm sure thankful for the online resources available. It save me some struggle by providing info not necessarily in the manual . I caught the cam position thing in the Honda manual because I had recently read it on TT. I stumbled on a video of a guy showing you how to get the rocker box cover off while the engine is in the frame. That was gold. Not knowing that, I may have gave up and removed the engine, which is the directions in the manual. I'm sure it has happened to somebody. Then the cam chain tensioner tool, I was in the process of manufacturing something when I looked online for better pictures of the tool, so I could wrap my mind around how it worked, (see pics) when I found a how to, from a guy showing you how to do it with a zip tie! Beautiful.